The objective of this research is to study the functional properties of abnormal human hemoglobins by measuring their oxygen binding equilibria under various controlled conditions of pH, organic phosphate, and other salt concentrations. The results will be used for two purposes. First, attempts will be made to correlate functional properties with structural alterations in order to extend our understanding of the contributions of specific amino acid residues in hemoglobin to its oxygen transport function. Second, attempts will be made to explain the presence or lack of clinical abnormalities such as erythrocytosis or anemia with specific abnormal hemoglobins. The studies will be divided into two levels of investigation. The first level is the screening of all previously unstudied and all new mutant hemoglobins available to our laboratory for general parameters of O2 binding (P50, Hill's "n" coefficient of cooperativity, Bohr effect, and influence of organic phosphates on P50 and "n"). The second level is the detailed study of those mutants with altered function. The results will be analyzed by the Adair equation and other models of hemoglobin oxygenation. Attempts will be made to examine different mutants of the same residue to more precisely define the influence of specific residues on the oxygen binding function. The principal methods used will be the measurement of oxygen equilibrium curves by the automatic recording system of Imai which measures fractional saturation of hemoglobin and oxygen pressure simultaneously over a range of less than 0.5% saturation to over 99% saturation. Computer storage and analysis of data will be used.